Today's loaders generally come equipped with one or another universal quick-attach apparatus for coupling with any of an array of specialty attachments and material handling implements. The predominant of these is the loader bucket, which is configured for attachment to the loader in an orientation in which the opening of the bucket remains forward-facing throughout its attainable range of motion. As such, any bucket's performance is thereby limited in its scope of operation to its forward thrust, rotation, and lift parameters, lacking the benefits that can be derived from an inversed, rearward facing configuration. Also, due to the same limits imposed by a forward-facing orientation, bucket width is generally limited to matching or exceeding the respective loader's overall width, as much narrower buckets tend to be impractical (i.e. in forward moving use, the bucket needs to be wide enough to clear a path for the loader to subsequently travel through). Generally, also, specialty attachments are, just like buckets, forwardly oriented and centrally fixed in coupling with the loader lift arms, lacking the benefits that can be derived from lateral manipulation, and for some, the benefits that can be derived from invertibility.
FIG. 15A illustrates a conventional back hoe arrangement on an excavation machine. The arrangement features a first boom 10 pivoted on a frame of the machine, a second boom 12 pivoted at the distal end of the first boom 10, and a back hoe bucket pivoted at the distal end of the second boom 12. Hydraulic actuators (not shown) are employed to articulate the arrangement about its four pivot points. Broken lines schematically illustrate the range of pivotal motion at each pivotal joint, demonstrating the suitability of the apparatus for trenching and deep-excavation, as the bucket can be manipulated back and forth through a range spanning from a downward-opening orientation in front of the second boom arm to a generally horizontal upward-opening orientation behind the second boom arm. Movement through this range in this order digs the downward-opening bucket into the ground, scoops the earth or other material into the bucket, where it can then be lifted away from the thusly excavated area, for example for later dumping in another area by swiveling of the excavator about an upright axis and then pivoting the bucket back through the reverse direction to revert the bucket to a downward opening orientation allowing the excavated material to fall from the bucket.
FIG. 15B illustrates a conventional front end loader configuration, such as that found on a tractor or skid steer. The number of pivot or articulation points between the frame and the machine is reduced compared to the backhoe. The machine features a pair of rigid arms 14 pivotally carried on opposite sides of the frame and linked to one another in front of the vehicle frame for movement together in parallel vertical planes by hydraulic actuators (not shown) acting to pivot the arms about their common pivot axis at the connection to the frame. At the front of these lift arms, the bucket attachment 16 is carried at a pivotal connection to the arms, and is also coupled to hydraulic actuators (not shown) on the arms to enable pivoting of the bucket about its pivotal connection to the lift arms. The connection between the frame and the lift arms and the connection between the bucket and the lift arms define the only two pivot or articulation axes of this conventional front end loader configuration.
A front end loader, in its standard forward configuration, is actually a formidable digging (excavating) machine, which is its intended primary function. In the simplest of terms, a forward movement of the machine, with the lowered bucket's nose tilted down would cause the material (earth or whatever) to be ‘forced’ into the bucket, and a subsequent lifting of the nose and lift arms effects a scooping action. The purpose of that action could be to a) just extract or move material for other use, or b) to carve or reshape the landscape. The loader, in requiring forward motion of the machine in order to do its work, must for every subsequent ‘bucketful’ enter the previously scooped spot. So its ability to ‘dig’ is in the nature of relatively shallow passes, and restricted to using only its standard large bucket. Taking the selected material away requires the picking up, backing up and turning and driving away and depositing movement of the machine itself.
Where a backhoe is substantially different in its operation, is that all the movements of the bucket; reach out and dig down, scoop, lift away, bring toward, move to the side, and deposit are all accomplished by articulation of the booms with the machine remaining stationary and outside the affected area. The bucket employed is relatively small. The machine's design targets deep-dig and trenching operations. In a backhoe, a prominent feature is having a rearward-facing bucket (or other implement) so that the mouth of it is facing and in plain view of the operator at all times (practically), so he can best direct and clearly see the results he's achieving.
Prior art devices have been proposed for converting a conventional front end loader configuration into a form having a bucket in an inverted rearward facing orientation.
FIG. 15C shows a solution proposed in U.S. Pat. No. 5,315,772 of Lalonde, where a smaller backhoe-type bucket 18 is attached to the existing loader bucket 16 of a utility tractor to lie beneath the bottom of the loader bucket in an orientation opening in the direction facing opposite the opening of the loader bucket. On its boom, at its nearest position vis a vis the host large bucket, the small bucket is at a distance from the pivot point no less than the overall span from the pivot point to the tip of the host bucket. It is also slave in its range of rotational motion to that of the leading edge of the host bucket. The backhoe bucket can thus dig into the ground, but without introducing another articulation point between the backhoe bucket and the loader bucket, the limited range of motion of the loader bucket prevents a full scooping action in which the backhoe bucket can be brought to a horizontal orientation opening upwardly between loader bucket and the front of the vehicle frame.
FIG. 15D shows a solution proposed in U.S. Pat. No. 6,119,377 of Rubio, where a smaller backhoe-type bucket 20 is part of an attachment 22 to be used in place of a conventional loader bucket of a skid steer loader. The attachment features a long boom arm that projects a notable distance from the connection of the attachment to the quick-attach device of the skid steer. A mounting bracket at the distal end of the boom features a number of different mounting holes for selective connection of the bucket at slightly different angles relative to the boom. Like with Lalonde's solution, the achievable range of motion of the bucket is again limited by the pivotal range achievable by the actuators on the lift arms around the pivotal connection at the end of the lift arms, and so a full scooping action may not be achievable. Instead, it is likely that the bucket initially digs into the ground and tilted to a maximum extent toward the machine about the pivotal connection to the lift arms, at which point lifting of the earth captured by the backhoe bucket is achieved by driving the machine in reverse to pull or drag the cut earth up out of the ground.
Another prior art attachment carrying an excavator bucket at the end of a boom arranged for selective connection to a front end loader is found in U.S. Pat. No. 2,815,137.
Other prior art solutions include the idea of adding a pivotal connection between the boom and bucket of a backhoe bucket attachment, and also add a hydraulic actuator on the boom for pivoting the bucket about this new articulation point. Examples of this are disclosed in U.S. Pat. Nos. 3,802,586, 4,571,146, 5,171,124, 2,788,906, 5,819,445, and 4,808,061. However, the addition of one or more extra actuators beyond those of the working machine itself adds the complexity of the solution, including the introduction of additional moving parts and the need for connection of a suitable power source (e.g. hydraulic output of the working machine) to the attachment for fully functional operation thereof.
Applicant has developed a number of unique attachment solutions for adapting a working machine with a conventional front end loader configuration into a rearward-opening inversed bucket configuration suitable for shallow excavation or scooping without reliance on additional actuators, beyond those of the machine itself, to achieve this scooping or shallow excavating motion.